Home Blood Pressure Measurements Will Not Replace 24-Hour Ambulatory Blood Pressure Monitoring

How to reliably diagnose arterial hypertension: lessons from 24 h blood pressure monitoring

BACKGROUND

Hypertension is a common condition in modern society. As blood pressure fluctuates with time, a single blood pressure measurement is useless to diagnose hypertension. Nevertheless, no well-defined number of measurements is often used for this purpose. Diagnosis and therapeutic control of hypertension are therefore suboptimal.

OBJECTIVE

To determine the number and timing of measurements needed to give a trustworthy approximation of an individual's average blood pressure.

METHODS

In this observational study 306 clinically indicated 24h ABPM datasets were analysed. Hypertension was defined as a daytime blood pressure mean exceeding 135/85 mm Hg. Kappa coefficients determined the best time of day for measuring blood pressure. The optimal number of measurements was estimated using canonical correlation.

RESULTS

162 (53%) patients were diagnosed with hypertension. Kappa statistics indicated that measuring during the afternoon gave the best agreement with the 24h blood pressure mean (κ = 0.78). According to canonical correlation, about 8-10 blood pressure readings give enough information for hypertension diagnosis.

CONCLUSIONS

Eight to ten blood pressure measurements between 01:00 and 05:00 p.m. are sufficient to give a clinically useful approximation of the daytime mean blood pressure and therefore for diagnosing hypertension accurately. Future research should determine the ideal dispersion of measurements and include patient characteristics which could influence the required number and timing of measurements. These results may increase the future importance of telemonitoring in diagnosing hypertension.

Ambulatory blood pressure monitoring in clinical practice

Being one of the most widely prevalent diseases throughout the world, hypertension has emerged as one of the leading causes of global premature morbidity and mortality. Hence, blood pressure (BP) measurements are essential for physicians in the diagnosis and management of hypertension. Current American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend initiating antihypertensive medications on the basis of office BP readings. However, office BP readings provide a snapshot evaluation of the patient's BP, which might not reflect patient's true BP, with the possibility of being falsely elevated or falsely low. Recently, there is ample evidence to show that ambulatory blood pressure monitoring (ABPM) is a better predictor of major cardiovascular events than BP measurements at clinic settings. ABPM helps in reducing the number of possible false readings, along with the added benefit of understanding the dynamic variability of BP. This article will focus on the significance of ambulatory BP, its advantages and limitations compared with the standard office BP measurement and a brief outlook on its use and interpretation to diagnose and treat hypertension.

Comparison of Optimal Diagnostic Thresholds of Hypertension With Home Blood Pressure Monitoring and 24-Hour Ambulatory Blood Pressure Monitoring

BACKGROUND

Differences between the recently suggested outcome-driven diagnostic threshold of home blood pressure (HBP) measurements and the currently recommended diagnostic threshold of HBP measurements may cause a disagreement between 24-hour ambulatory blood pressure (ABP) and HBP measurements in the diagnosis of hypertension. We evaluated the agreement of various HBP diagnostic thresholds (135/85, 130/85, and 130/80 mm Hg) to ABP measurements, as a reference method.

METHODS

Patients who were confirmed to have high BP (≥140/90 mm Hg) at the outpatient clinic were referred. HBP measurement was performed for 7 days in triplicates every morning and evening. The 24-hour ABP measurement was performed on the 8th day. Using 24-hour ABP measurement as a reference method, we analyzed HBP diagnostic thresholds at 135/85, 130/85, and 130/80 mm Hg.

RESULTS

Among 319 patients, 256 patients (mean age, 51.8 ± 9.7 years; 119 men) with valid HBP measurements and 24-hour ABP measurements were enrolled. The threshold of 130/80 mm Hg showed the highest diagnostic sensitivity (P = 0.001) with diagnostic agreement by Kappa statistics. Using 130/80 mm Hg as a diagnostic threshold of hypertension, the prevalence of masked hypertension was significantly lower than 130/85 and 135/85 mm Hg (7.8, 15.2, and 18.4%, respectively, P = 0.002).

CONCLUSIONS

The present study suggests that lowering the diagnostic thresholds of HBP measurement from 135/85 mm Hg to 130/80 mm Hg may improve diagnostic accuracy for hypertension.

Breathing Training for Older Patients with Controlled Isolated Systolic Hypertension

INTRODUCTION

Isolated systolic hypertension (ISH) is very common but difficult to manage with conventional medication. We investigated whether slow breathing training, with and without an inspiratory load, could reduce the resting blood pressure of older well-managed ISH patients.

METHODS

Thirty ISH patients (66 ± 4 yr) were randomized into loaded breathing (six breaths per min, 18 cm H2O), unloaded breathing (six breaths per min, no load), or control (normal breathing) groups. After a 2-wk run-in, loaded and unloaded groups trained at home for 30 min every day for 8 wk. Morning home blood pressure and heart rate were measured daily throughout the study. At the end of training, all participants reverted to normal breathing, and blood pressure and heart rate were recorded for a further 8 wk.

RESULTS

Compared to the pretraining run-in period, systolic blood pressure was reduced by 18 ± 7 and 11 ± 4 mm Hg for loaded and unloaded groups, respectively (P < 0.001), the reduction being significantly larger for the loaded group (P < 0.05) after 8-wk training. There were no changes in the control group. After the end of training, systolic blood pressure remained below pretraining levels for a further 6 wk for the loaded group but for only 2 wk with the unloaded group. There was a small nonsignificant reduction in diastolic blood pressure with training, as there was for heart rate. Pulse pressures were reduced by 11 ± 5 and 5 ± 6 mm Hg for loaded and unloaded groups, respectively (P < 0.01).

CONCLUSION

Slow breathing training, especially with an inspiratory load, is very effective in reducing resting systolic and pulse pressures and could be a valuable adjunct in the management of ISH.

Ambulatory blood pressure variability: a conceptual review

Ambulatory blood pressure (ABP) has long been recognized by researchers as the gold standard of blood pressure (BP) measurement. Researchers and clinicians typically rely on the mean measure of ABP; however, there is considerable variability in the beat-to-beat BP. Although often ignored, this variability has been found to be an independent predictor of cardiovascular disease and mortality. The aim of this paper is to provide a conceptual review of ABP variability (ABPV) focusing on the following: associations between ABPV and health, whether ABPV is reliable, how to calculate ABPV, predictors of ABPV, and treatments for ABPV. Two future directions are discussed involving better understanding ABPV by momentary assessments and improving knowledge of the underlying physiology that explains ABPV. The results of this review suggest that the unique characteristics of ABPV provide insight into the role of BP variability in hypertension and subsequent cardiovascular illness.

Night-time home versus ambulatory blood pressure in determining target organ damage

OBJECTIVE

This study aimed to evaluate the association of night-time blood pressure (BP) assessed by home blood pressure (HBP) or ambulatory blood pressure (ABP) monitoring with preclinical target organ damage in untreated hypertension.

METHODS

Untreated hypertensive study participants were evaluated with ABP monitoring (24-h) and HBP monitoring during daytime (6 days, duplicate morning and evening measurements) and night-time (automated asleep measurements, three nights, 3-hourly measurements/night). Target organ damage was assessed by echocardiographic left ventricular mass index (LVMI), common carotid intima-media thickness (cIMT), urine albumin excretion (UAE), and ankle-brachial index (ABI).

RESULTS

A total of 131 study participants were analysed [mean age 52.1 ± 11.9 (SD) years, BMI 29.9 ± 5.3  kg/m2, men 58%, cardiovascular disease history 6.1%]. Daytime and night-time HBP were slightly higher than the respective ABP values (mean difference for systolic daytime/night-time 3.5 ± 10.6/2.6 ± 9.8  mmHg, P < 0.01 for both comparisons and diastolic -0.3 ± 6.8/1.2 ± 6.2  mmHg, P = NS/0.02, respectively). There was a strong correlation between daytime ABP and HBP (r = 0.71/0.72, systolic/diastolic), as well as between the respective night-time values (r = 0.80/0.79; all P < 0.01). Night-time ABP and HBP presented strong and comparable correlations with all the indices of preclinical target organ damage. In multivariate analyses, both LVMI (R2 = 0.26) and cIMT (R2 = 0.25) were determined by night-time systolic HBP, age and male sex; UAE (R2 = 0.28) by night-time systolic HBP and male sex; ABI (R2 = 0.20) by male sex and night-time home pulse pressure.

CONCLUSION

In untreated hypertensives, night-time BP assessed by home monitoring appears to be as good as night-time ambulatory monitoring in determining preclinical target organ damage.

Masked Hypertension and Cardiovascular Disease Events in a Prospective Cohort of Blacks: The Jackson Heart Study

Masked hypertension, defined as nonelevated clinic blood pressure (BP) with elevated out-of-clinic BP, has been associated with increased cardiovascular disease (CVD) risk in Europeans and Asians. Few data are available on masked hypertension and CVD and mortality risk among blacks. We analyzed data from the Jackson Heart Study, a prospective cohort study of blacks. Analyses included participants with clinic-measured systolic/diastolic BP <140/90 mm Hg who completed ambulatory BP monitoring after the baseline examination in 2000 to 2004 (n=738). Masked daytime (10:00 am-8:00 pm) hypertension was defined as mean ambulatory systolic/diastolic BP ≥135/85 mm Hg. Masked nighttime (midnight to 6:00 am) hypertension was defined as mean ambulatory systolic/diastolic BP ≥120/70 mm Hg. Masked 24-hour hypertension was defined as mean systolic/diastolic BP ≥130/80 mm Hg. CVD events (nonfatal/fatal stroke, nonfatal myocardial infarction, or fatal coronary heart disease) and deaths identified through December 2010 were adjudicated. Any masked hypertension (masked daytime, nighttime, or 24-hour hypertension) was present in 52.2% of participants; 28.2%, 48.2% and 31.7% had masked daytime, nighttime, and 24-hour hypertension, respectively. There were 51 CVD events and 44 deaths during a median follow-up of 8.2 and 8.5 years, respectively. CVD rates per 1000 person-years (95% confidence interval) in participants with and without any masked hypertension were 13.5 (9.9-18.4) and 3.9 (2.2-7.1), respectively. The multivariable adjusted hazard ratio (95% confidence interval) for CVD was 2.49 (1.26-4.93) for any masked hypertension and 2.86 (1.59-5.13), 2.35 (1.23-4.50), and 2.52 (1.39-4.58) for masked daytime, nighttime, and 24-hour hypertension, respectively. Masked hypertension was not associated with all-cause mortality. Masked hypertension is common and associated with increased risk for CVD events in blacks.

Studies comparing ambulatory blood pressure and home blood pressure on cardiovascular disease and mortality outcomes: a systematic review

Ambulatory blood pressure monitoring (ABPM) is more commonly recommended for assessing out-of-clinic blood pressure (BP) than home blood pressure monitoring (HBPM). We conducted a systematic review to examine whether ABPM or HBPM is more strongly associated with cardiovascular disease events and/or mortality. Of 1007 abstracts published through July 20, 2015, nine articles, reporting results from seven cohorts, were identified. After adjustment for BP on HBPM, BP on ABPM was associated with an increased risk of outcomes in two of four cohorts for systolic blood pressure and two of three cohorts for diastolic blood pressure. After adjustment for BP on ABPM, systolic blood pressure on HBPM was associated with outcomes in zero of three cohorts; an association was present in one of two cohorts for diastolic blood pressure on HBPM. There is a lack of strong empiric evidence supporting ABPM or HBPM over the other approach for predicting cardiovascular events or mortality.

Role of Ambulatory and Home Blood Pressure Monitoring in Clinical Practice: A Narrative Review

Hypertension, a common risk factor for cardiovascular disease, is usually diagnosed and treated based on blood pressure readings obtained in the clinic setting. Blood pressure may differ considerably when measured inside versus outside of the clinic setting. Over the past several decades, evidence has accumulated on the following 2 approaches for measuring blood pressure outside of the clinic: ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM). Both of these methods have a stronger association with cardiovascular disease outcomes than clinic blood pressure measurement. Controversy exists about whether ABPM or HBPM is superior for estimating risk for cardiovascular disease and under what circumstances these methods should be used in clinical practice for assessing blood pressure outside of the clinic. This review describes ABPM and HBPM procedures, the blood pressure phenotypic measurements that can be ascertained, and the evidence that supports the use of each approach to measuring blood pressure outside of the clinic. It also describes barriers to the successful implementation of ABPM and HBPM in clinical practice, proposes core competencies for the conduct of these procedures, and highlights important areas for future research.

Ambulatory blood pressure monitoring in the elderly: features and perspectives

Aging leads to a multitude of changes in the cardiovascular system that include a rise in blood pressure. Age-related changes in blood pressure are mainly attributable to an increase in systolic blood pressure, generally associated with a slight decrease diastolic blood pressure. This leads to a widening in pulse pressure. Ambulatory blood pressure monitoring is a useful tool to understand these processes and to refine cardiovascular risk assessment. In the light of emerging data in this area, we reviewed the main features of ambulatory blood pressure in elderly and discussed the evidence showing that ambulatory blood pressure is superior to clinic blood pressure to reflect the true pattern of blood pressure over time. Furthermore, we discussed the role of weight control obtained by fitness programs to prevent an excessive rise in blood pressure with age. A thorough understanding of these concepts is of paramount importance and has therapeutic implications in the growing population of elderly subjects with increased blood pressure.

Obese hypertensive men have plasma concentrations of C-reactive protein similar to that of obese normotensive men

BACKGROUND

Low-grade chronic inflammation is a characteristic feature of obesity, the most important lifestyle risk factor for hypertension. Elevated plasma concentrations of the inflammatory biomarker C-reactive protein (CRP) are associated with an increased risk of hypertension, but elevated plasma CRP concentrations are also closely associated with obesity. It is uncertain whether CRP is directly involved in the pathogenesis of hypertension or is only a marker of other pathogenic processes closely related to obesity.

METHODS

We studied 103 obese men (body mass index (BMI) ≥ 30.0 kg/m(2)); 63 of these men had 24-hour ambulatory blood pressure (ABP) ≥ 130/80 mm Hg and comprised the obese hypertensive (OHT) group. The 40 remaining obese men had 24-hour ABP < 130/80 mm Hg and comprised the obese normotensive (ONT) group. Our control group comprised 27 lean normotensive (LNT) men. All participants were medication-free. We measured plasma CRP concentrations with a high-sensitivity assay and determined body composition by dual energy x-ray absorptiometry scanning.

RESULTS

There were no differences in anthropometric measures (BMI, waist circumference, or total fat mass percentage) between OHT and ONT groups (P ≥ 0.08). The obese groups had higher CRP concentrations than the LNT group (OHT: median = 2.30, interquartile range (IQR) = 1.10-4.10mg/L; ONT: median = 2.55, IQR = 1.25-4.80 mg/L; LNT: median = 0.60, IQR = 0.30-1.00 mg/L; P < 0.001), but there was no difference in CRP concentrations between OHT and ONT groups (P = 1.00). In the obese men, CRP was not correlated with either 24-hour systolic (r = 0.04; P = 0.71) or 24-hour diastolic ABP (r = -0.03; P = 0.78).

CONCLUSIONS

Obese hypertensive men, matched for anthropometric measurements, have plasma CRP concentrations similar to those of obese normotensive men.

Clinical significance of home blood pressure measurements for the prevention and management of high blood pressure

1. Ambulatory blood pressure (ABP) monitoring (M) provides BP information at many points on any particular day during unrestricted routine daily activities, whereas home blood pressure (HBP) monitoring provides a lot of BP information obtained under fixed times and conditions over a long period of time, thus mean values of HBP provide high reproducibility, and thus an overall superiority compared with ABP.  2. HBP is at least equally or better able than ABP to predict hypertensive target organ damage and prognosis of cardiovascular disease.  3. HBPM allows for ongoing disease monitoring by patients, improves adherence to antihypertensive treatment, and can provide health-care providers with timely clinical data and direct and immediate feedback regarding diagnosis and treatment of hypertension.  4. HBPM provides BP information in relation to time; that is, BP in the morning, in the evening and at night during sleep, and it is an essential tool for the diagnosis of white-coat and masked hypertension.  5. HBPM yields minimal alerting affects and no or minimal placebo effect, and can therefore distinguish small, but significant, serial changes in BP. It is thus the most practical method for monitoring BP in the day-to-day management of hypertension. 6. The superiority of HBPM over ABPM and clinic BPM is apparent from almost all practical and clinical research perspectives.

Copeptin, a surrogate marker for arginine vasopressin secretion, is associated with higher glucose and insulin concentrations but not higher blood pressure in obese men

AIM

To explore the putative associations of plasma copeptin, the C-terminal portion of provasopressin and a surrogate marker for arginine vasopressin secretion, with obesity-related health problems, such as hyperlipidaemia, hyperinsulinaemia, hyperglycaemia, high blood pressure and an android fat distribution.

METHODS

In 103 obese men (mean age ± standard deviation: 49.4 ± 10.2 years) and 27 normal weight control men (mean age: 51.5 ± 8.4 years), taking no medication, we measured 24-h ambulatory blood pressure, fasting blood concentrations of copeptin, lipids, glucose and insulin, and determined body composition by dual energy X-ray absorptiometry scanning.

RESULTS

The obese men had higher [median (interquartile range)] plasma copeptin concentrations [6.6 (4.6-9.5) vs. 4.9 (3.5-6.8) pmol/l, P = 0.040] compared with the normal weight men. In the obese men, plasma copeptin was not related to 24-h systolic blood pressure (r = 0.11, P = 0.29), 24-h diastolic blood pressure (r = 0.11, P = 0.28), BMI (r = 0.09, P = 0.37), total body fatness percentage (r = 0.10, P = 0.33), android fat mass percentage (r = 0.04, P = 0.66) or serum triglyceride concentrations (r = 0.04; P = 0.68). In contrast, plasma copeptin was associated with higher serum insulin concentrations (r = 0.26, P = 0.0085) and insulin resistance as assessed by the homeostasis assessment model (r = 0.28, P = 0.0051).

CONCLUSIONS

Plasma copeptin, a surrogate marker for arginine vasopressin secretion, is higher in obese men compared with normal weight men, and is associated with abnormalities in glucose and insulin metabolism, but not with higher blood pressure or an android fat distribution in obese men.

Relative atrial natriuretic peptide deficiency and inadequate renin and angiotensin II suppression in obese hypertensive men

Obesity is a strong risk factor for hypertension, but the mechanisms by which obesity leads to hypertension are incompletely understood. On this background, we assessed dietary sodium intake, serum levels of natriuretic peptides (NPs), and the activity of the renin-angiotensin system in 63 obese hypertensive men (obeseHT: body mass index, ≥30.0 kg/m(2); 24-hour ambulatory blood pressure, ≥130/80 mm Hg), in 40 obese normotensive men (obeseNT: body mass index, ≥30.0 kg/m(2); 24-hour ambulatory blood pressure, <130/80 mm Hg), and in 27 lean normotensive men (leanNT: body mass index, 20.0-24.9 kg/m(2); 24-hour ambulatory blood pressure, <130/80 mm Hg). All study subjects were medication free. As a surrogate estimate for dietary sodium intake, we measured sodium excretion in a 24-hour urine collection and we measured serum levels of midregional proatrial NP and plasma levels of renin and angiotensin II. The obese men had higher mean (±SD) urinary sodium excretion (obeseHT, 213.6±85.2 mmol; obeseNT, 233.0±70.0 mmol) than the lean normotensive men (leanNT, 155.5±51.7 mmol; P=0.003). ObeseHT had lower (median [interquartile range]) serum midregional proatrial NP levels (49.2 [37.3-64.7] pmol/L) than leanNT (69.3 [54.3-82.9] pmol/L; P=0.003), whereas obeseNT had midregional proatrial NP levels in between (54.1 [43.2-64.7] pmol/L); obeseNT had lower (median [interquartile range]) plasma levels of renin (5.0 [3.0-8.0] mIU/L versus 9.0 [4.0-18.0]) and angiotensin II (2.4 [1.5-3.5] pmol/L versus 4.2 [2.2-7.9]) than obeseHT (P≤0.049), whereas obeseHT had similar plasma levels of renin and angiotensin II as leanNT (P≥0.19). Thus, despite a high sodium intake and a high blood pressure, obese hypertensive men have a relative NP deficiency and an inadequate renin-angiotensin system suppression.

Antihypertensive therapy: nocturnal dippers and nondippers. Do we treat them differently?

Hypertension is a major independent risk factor for cardiovascular diseases. Management of hypertension is generally based on office blood pressure since it is easy to determine. Since casual blood pressure readings in the office are influenced by various factors, they do not represent basal blood pressure. Dipping of the blood pressure in the night is a normal physiological change that can be blunted by cardiovascular risk factors and the severity of hypertension. Nondipping pattern is associated with disease severity, left ventricular hypertrophy, increased proteinuria, secondary forms of hypertension, increased insulin resistance, and increased fibrinogen level. Long-term observational studies have documented increased cardiovascular events in patients with nondipping patterns. Nocturnal dipping can be improved by administering the antihypertensive medications in the night. Long-term clinical trials have shown that cardiovascular events can be reduced by achieving better dipping patterns by administering medications during the night. Identifying the dipping pattern is useful for decisions to investigate for secondary causes, initiating treatment, necessity of chronotherapy, withdrawal or reduction of unnecessary medications, and monitoring after treatment initiation. Use of this concept at the primary care level has been limited because 24-hour ambulatory blood pressure monitoring has been the only method for documenting dipping/nondipping status so far. This monitoring technique is expensive and inconvenient for routine usage. Simpler methods using home blood pressure monitoring systems are evolving to document basal blood pressure in the night, which would help in greater acceptance and use of the concept of dipper/nondipper in managing hypertension at the primary care level.

Genetic variation in the natriuretic peptide system, circulating natriuretic peptide levels, and blood pressure: an ambulatory blood pressure study

BACKGROUND

In a large collaborative study (n > 50,000), common variants in the natriuretic peptide (NP) genes were found to be associated with circulating NP levels and also with blood pressure (BP) levels based on office BP measurements (OBPMs). It is unknown if determining an individual's BP by 24-h ambulatory BP measurements (ABPMs) will influence the effect of NP gene variations on BP levels.

METHODS

We used rs632793 at the NPPB (NP precursor B) locus to investigate the relationship between genetically determined serum N-terminal pro-brain NP (NT-proBNP) concentrations and BP levels determined by both 24-h ABPMs and OBPMs in a population consisting of 1,397 generally healthy individuals taking no BP-lowering drugs.

RESULTS

rs632793 was significantly correlated with serum Nt-proBNP levels (r = 0.10, P = 0.0003), and participants with the A:A genotype had lower serum Nt-proBNP levels than participants with the G:G genotype (geometric mean (95% confidence interval (CI)): 34.8 (31.5-38.4) pg/ml vs. 48.1 (41.9-55.3) pg/ml, P = 0.0002), but higher 24-h ambulatory BP levels (mean difference (95% CI): 2.0 (0.1-4.1) mm Hg, P = 0.043, for systolic BP and 1.7 (0.4-3.1) mm Hg, P = 0.011, for diastolic BP). Office BP decreased across the genotypes from A:A to G:G, but the differences did not reach statistical significance (P ≥ 0.12).

CONCLUSIONS

This study suggests that 24-h ABPMs is a better method than OBPMs to detect significant differences in BP levels related to genetic variance and provides further evidence that the NP system plays an important role in BP regulation.

Elderly hypertensives: how are they different?

Once considered an inconsequential part of the aging process, the development of isolated systolic hypertension represents a late manifestation of increased elastic artery stiffness and is the predominant hypertensive subtype in the middle-aged and elderly populations. Its inherent increased risk for vascular events, such as coronary heart disease, stroke, heart failure, peripheral artery disease, chronic kidney disease, and dementia, highlights the importance of its control. The purpose of this short review is to summarize how hypertension is different in the elderly when compared with "essential hypertension" in younger adults. The emphasis will be on the multiple ways that increased artery stiffness affects the natural history and clinical manifestations of hypertension in the elderly.

Effects of treatment with oral appliance on 24-h blood pressure in patients with obstructive sleep apnea and hypertension: a randomized clinical trial

BACKGROUND

Continuous positive airway pressure treatment has been shown to lower blood pressure (BP) in patients with obstructive sleep apnea (OSA). The aims of the present pilot study were to evaluate the potential effects of oral appliance (OA) therapy on BP, to assess various outcome BP measures, and to inform sample size calculation.

METHODS

Seventy-two patients with OSA and hypertension were randomly assigned to intervention with either an OA with mandibular advancement (active group) or an OA without advancement (control group). Before and after 3 months of treatment, the patients underwent nocturnal somnographic registration and 24-h ambulatory BP monitoring.

RESULTS

Among the various BP measures, the largest trend toward effect of OA treatment was seen in 24-h mean systolic BP with a 1.8 mmHg stronger BP reduction in the active group compared with controls. A stronger trend toward effect was seen in a subgroup with baseline ambulatory daytime mean systolic BP >135/85 mmHg where the mean systolic BP fell, on average, 2.6 mmHg. Additional exclusion of patients with baseline apnea hypopnea index (AHI) ≤15 gave a significant reduction in mean systolic BP of 4.4 mmHg (P = 0.044) in the active group compared with controls.

CONCLUSIONS

In patients with OSA and hypertension, OA treatment had a modest trend toward effect on reducing BP. A stronger trend toward treatment effect was seen after excluding patients with normal baseline ambulatory BP. Additional exclusion of patients with baseline AHI ≤15 showed a significant treatment effect. Data to inform sample size for an adequately powered randomized study are provided.

Fibrillin-1 genotype and risk of prevalent hypertension: a study in two independent populations

OBJECTIVE

Mutations in the fibrillin-1 gene are the cause of Marfan syndrome. We wanted to investigate the relationship between a mutation in this gene and risk of prevalent hypertension.

METHODS

In a cross-sectional study, the effect of a G-A substitution in intron 27 in the fibrillin-1 gene (rs11856553) on risk of prevalent hypertension was studied in two large population-based studies: the Health 2006 study, consisting of 3193 women and men, age 18-69 years, and the MONICA10 study, consisting of 2408 women and men, age 41-72 years. In 1646 MONICA10 participants, blood pressure (BP) was also measured by 24-h ambulatory recordings.

RESULTS

Among the 3193 Health 2006 participants 23 had the G-A variant, and among the 2408 MONICA10 participants 18 had the G-A variant. In Health 2006, the odds ratio estimate (95% confidence intervals) for the G-A variant for risk of hypertension, defined as systolic (S) BP ≥ 140 mmHg or diastolic (D) BP ≥ 90 mmHg or on antihypertensive medicine, was 2.67 (1.14-6.18), p = 0.022. The corresponding figure for moderate to severe hypertension, defined as SBP ≥ 160 mmHg or DBP ≥ 100 mmHg, was 9.68 (4.24-22.12), p < 0.0001. In MONICA10, the odds ratio estimate (95% confidence intervals) for the G-A variant for risk of moderate to severe ambulatory hypertension, defined as 24-h mean SBP ≥ 150 mmHg or 24-h mean DBP ≥ 90 mmHg, was 5.73 (1.96-16.7), p = 0.0014.

CONCLUSION

The G-A substitution in the fibrillin-1 gene (rs11856553) is a rare genetic variant that is associated with an increased risk of prevalent hypertension, particularly of moderate to severe prevalent hypertension.

[Measurement of blood pressure in consultation and automated mesurement (BPTru(®)) to evaluate the white coat effect]

BACKGROUND AND OBJECTIVE

White coat effect (WCE) is one of the main bias that can affect office blood pressure (BP) measurement. Therefore, it is a factor must be considered in hypertensives to avoid mistakes in diagnosis and/or treatment. Employment of automated office BP (AOBP) devices could diminish that effect.

METHODS

Two studies were designed with the objective of evaluating differences between routinely office and AOBP measurements. WCE was also assessed. First, the TRUE-ESP study included normotensive and hypertensive patients attending specialized consultations at Cardiology, Nephrology, Internal Medicine, Endocrinology and Family Practice. Second, the TRUE-HTA study included hypertensives attending a protocoled Hypertension Unit, with a trained staff.

RESULTS

TRUE-ESP study included 300 patients, 76% being hypertensives. A significant difference between office BP and AOBP measurement (SBP/DBP 9.8±11.6/3.4±7.9 mmHg, P<.001) was observed. Percentage of patients gathering WCE criteria was 27.7%. TRUE-HTA study included 101 hypertensive patients. A significant difference between office BP and AOBP measurement (SBP/DBP 5.7±9.3/2.1±5.3 mmHg, P<.001) and activity period-ABPM (SBP/DBP 8.5±6.7/3.5±2.5 mmHg, P<.001) was observed. Percentage of WCE patients was 32.1%.

CONCLUSIONS

Use of AOBP devices can contribute to decrease WCE and to improve accuracy of office BP measurement.

Association of home and ambulatory blood pressure changes with changes in cardiovascular biomarkers during antihypertensive treatment

BACKGROUND

Our aim was to assess whether home blood pressure (HBP) and ambulatory BP monitoring measurement (ABPM), in addition to office BP (OBP) predict changes of cardiovascular biomarkers during antihypertensive treatment.

METHODS

Two hundred and fifty-two hypertensive patients (mean age, 68 years; men: 41%) underwent measurements of OBP, HBP, ABPM, and cardiovascular biomarkers (urinary albumin excretion (UAE) and brain natriuretic peptide (BNP)) before and after 6 months of treatment with candesartan (± thiazide-diuretics).

RESULTS

During the intervention, the OBP, HBP, daytime and night-time BP, and UAE levels were all significantly reduced (all P < 0.01). BNP was reduced only in the patients using diuretics (P = 0.003). For predicting the treatment-induced change in UAE, each of home systolic BP (SBP) and night-time SBP changes, but not daytime SBP change, had independent and significant value beyond OBP measurement (both P < 0.05). In contrast, for predicting the treatment-induced change in BNP, night-time SBP changes, but not home or daytime SBP changes, had significant value beyond OBP measurement (both P < 0.05). Patients who achieved a reduction in all three SBP parameters (office, home, and night-time SBP; n = 122) showed a more significant reduction of UAE compared with those who did not (-52.6 vs. -32.5%; P = 0.001), and patients who achieved a reduction in both office and night-time SBP (n = 134) showed a more significant reductions of BNP than those who did not (-12.9 vs. +12.8%; P < 0.05).

CONCLUSIONS

HBP and ABPM measurements, particularly night-time SBP values provide additional information for predicting treatment-induced changes of cardiovascular biomarkers when used in conjunction with office SBP measurement during antihypertensive treatment.

Why use automated office blood pressure measurements in clinical practice?

Automated office blood pressure (AOBP) measurement with the patient resting alone in a quiet examining room can eliminate the white-coat effect associated with conventional readings taken by manual sphygmomanometer. The key to reducing the white-coat response appears to be multiple blood pressure (BP) readings taken in a non-observer office setting, thus eliminating any interaction that could provoke an office-induced increase in BP. Furthermore, AOBP readings have shown a higher correlation with the mean awake ambulatory BP compared with BP readings recorded in routine clinical practice. Although there is a paucity of studies connecting AOBP with organ damage, AOBP values were recently found to be equally associated with left ventricular mass index as those of ambulatory BP. This concludes that in contrast to routine manual office BP, AOBP readings compare favourably with 24-hour ambulatory BP measurements in the appraisal of cardiac remodelling and, as such, could be complementary to ambulatory readings in a way similar to home BP measurements.

Significance of white-coat hypertension in older persons with isolated systolic hypertension: a meta-analysis using the International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes population

The significance of white-coat hypertension in older persons with isolated systolic hypertension remains poorly understood. We analyzed subjects from the population-based 11-country International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes database who had daytime ambulatory blood pressure (BP; ABP) and conventional BP (CBP) measurements. After excluding persons with diastolic hypertension by CBP (≥90 mm Hg) or by daytime ABP (≥85 mm Hg), a history of cardiovascular disease, and persons <18 years of age, the present analysis totaled 7295 persons, of whom 1593 had isolated systolic hypertension. During a median follow-up of 10.6 years, there was a total of 655 fatal and nonfatal cardiovascular events. The analyses were stratified by treatment status. In untreated subjects, those with white-coat hypertension (CBP ≥140/<90 mm Hg and ABP <135/<85 mm Hg) and subjects with normal BP (CBP <140/<90 mm Hg and ABP <135/<85 mm Hg) were at similar risk (adjusted hazard rate: 1.17 [95% CI: 0.87-1.57]; P=0.29). Furthermore, in treated subjects with isolated systolic hypertension, the cardiovascular risk was similar in elevated conventional and normal daytime systolic BP as compared with those with normal conventional and normal daytime BPs (adjusted hazard rate: 1.10 [95% CI: 0.79-1.53]; P=0.57). However, both treated isolated systolic hypertension subjects with white-coat hypertension (adjusted hazard rate: 2.00; [95% CI: 1.43-2.79]; P<0.0001) and treated subjects with normal BP (adjusted hazard rate: 1.98 [95% CI: 1.49-2.62]; P<0.0001) were at higher risk as compared with untreated normotensive subjects. In conclusion, subjects with sustained hypertension who have their ABP normalized on antihypertensive therapy but with residual white-coat effect by CBP measurement have an entity that we have termed, "treated normalized hypertension." Therefore, one should be cautious in applying the term "white-coat hypertension" to persons receiving antihypertensive treatment.

Masked inefficacy of arterial hypertension treatment: prevalence and predictors

Aim.To assess the prevalence of masked inefficacy of arterial hypertension treatment (AH MTI) and its predictors in various clinical groups and for various blood pressure (BP) control strategies, in order to evaluate the true effectiveness of antihypertensive therapy (AHT).Material and methods.AHT effectiveness was assessed in two groups of the patients with Stage I-II AH (n=219 and n=39), by comparing the ratios of clinical (cl) to ambulatory (a) BP parameters. AH MTI was defined as elevated aBP and target clBP levels during AHT. The potential predictors of AH MTI included gender, age, body mass index (BMI), anamnestic data, frequency of the clinical visits to measure BP, quality of life (QoL) parameters (GWBQ questionnaire), circadian BP profile, orthostatic BP, and ECG signs of left ventricular hypertrophy (LVH).Results.AH MTI prevalence in Groups I and II was 11,0-15,7 % and 22,6-58,1 %, respectively, depending on the definition used. The groups were significantly different in terms of age, BMI, and QoL questionnaire III and VI domains. According to the regression analysis results, in Group I AH MTI was associated with QoL questionnaire II, V, and VI domains, baseline parameters of 24-hour BP monitoring, 24-hour systolic BP (SBP) variability, minimal daytime levels of mean BP, and metoprolol and atenolol therapy. In Group II, AH MTI was predicted by age, BMI, previously administered AHT, alcohol consumption, orthostatic SBP levels, Sokolow-Lyon index, Cornell voltage and Cornell product, Gubner index, and QoL questionnaire I, IV, and VI domains.Conclusion.AH MTI prevalence is associated with some baseline characteristics of the patients and the character of AHT. Due to regression to the mean, AH MTI prevalence could increase substantially when clBP parameters are measured more often.

Obstructive sleep apnea and systemic hypertension: longitudinal study in the general population: the Vitoria Sleep Cohort

RATIONALE

Obstructive sleep apnea and systemic hypertension (SH) are highly prevalent. Although their association has been suggested in cross-sectional studies, conflicting evidence has emerged from longitudinal studies.

OBJECTIVES

To assess the association between obstructive sleep apnea and SH in the middle-aged general population.

METHODS

A total of 2,148 subjects were included in a longitudinal study of the Vitoria Sleep Cohort, a general population sample aged 30-70 years. We analyzed data on office blood pressure, anthropometric measures, health history, and home polygraphy. Out of 1,557 subjects who completed the 7.5-year follow-up, 377 were excluded for having SH at baseline. The odds ratios for the incidence of SH, according to the respiratory disturbance index (RDI) at baseline, were estimated in 1,180 subjects (526 men and 654 women) after adjustment for age; sex; body mass index; neck circumference; fitness level; and alcohol, tobacco, and coffee consumption. The RDI was divided into quartiles (0-2.9, 3-6.9, 7-13.9, and ≥ 14), using the first quartile as reference.

MEASUREMENTS AND MAIN RESULTS

The crude odds ratio for incident hypertension increased with higher RDI category with a dose-response effect (P < 0.001), but was not statistically significant after adjustment for age (P = 0.051). Adjustments for sex (P = 0.342), body mass index (P = 0.803), neck circumference (P = 0.885), and fitness level and alcohol, tobacco, and coffee consumption (P = 0.708) further reduced the strength of the association between RDI and SH. No differences were observed between men and women.

CONCLUSIONS

Our findings do not suggest an association between obstructive sleep apnea and the incidence of SH in the middle-aged general population. Long-term follow-up longitudinal studies are needed to better ascertain this association.

Central versus ambulatory blood pressure in the prediction of all-cause and cardiovascular mortalities

OBJECTIVES

Central systolic (SBP-C) and/or pulse pressure (PP-C) better predicts cardiovascular events than does peripheral blood pressure. The present study compared the prognostic significance of office central blood pressure with multiple measurements of out-of-office ambulatory peripheral blood pressure, with reference to office peripheral systolic (SBP-B) or pulse pressure (PP-B).

METHODS

In a community-based population of 1014 healthy participants, SBP-C and PP-C were estimated using carotid tonometry, and 24-h systolic (SBP-24 h) and pulse pressure (PP-24 h) were obtained from 24-h ambulatory blood pressure monitoring. Associations of SBP-B, PP-B, SBP-C, PP-C, SBP-24 h, and PP-24 h with all-cause and cardiovascular mortalities over a median follow-up of 15 years were examined by Cox regression analysis.

RESULTS

In multivariate analyses accounting for age, sex, BMI, smoking, fasting plasma glucose, and total cholesterol/high-density lipoprotein cholesterol ratio, only PP-C (hazard ratio 1.16, 95% confidence interval 1.01-1.32, per one standard deviation increment) was significantly predictive of all-cause mortality, whereas all but PP-B were significantly predictive of cardiovascular mortality. When SBP-B was simultaneously included in the models, SBP-24 h (2.01, 1.42-2.85) and SBP-C (1.71, 1.21-2.40) remained significantly predictive of cardiovascular mortality. When SBP-C was simultaneously included in the models, SBP-24 h (1.71, 1.16-2.52) remained significantly predictive of cardiovascular mortality.

CONCLUSION

Office central blood pressure is more valuable than office peripheral blood pressure in the prediction of all-cause and cardiovascular mortalities. Out-of-office ambulatory peripheral blood pressure (SBP-24 h) may be superior to central blood pressure in the prediction of cardiovascular mortality, but PP-C may better predict all-cause mortality than SBP-24 h or PP-24 h.

Conventional versus automated measurement of blood pressure in primary care patients with systolic hypertension: randomised parallel design controlled trial

OBJECTIVE

To compare the quality and accuracy of manual office blood pressure and automated office blood pressure using the awake ambulatory blood pressure as a gold standard.

DESIGN

Multi-site cluster randomised controlled trial.

SETTING

Primary care practices in five cities in eastern Canada.

PARTICIPANTS

555 patients with systolic hypertension and no serious comorbidities under the care of 88 primary care physicians in 67 practices in the community.

INTERVENTIONS

Practices were randomly allocated to either ongoing use of manual office blood pressure (control group) or automated office blood pressure (intervention group) using the BpTRU device. The last routine manual office blood pressure (mm Hg) was obtained from each patient's medical record before enrollment. Office blood pressure readings were compared before and after enrollment in the intervention and control groups; all readings were also compared with the awake ambulatory blood pressure.

MAIN OUTCOME MEASURE

Difference in systolic blood pressure between awake ambulatory blood pressure minus automated office blood pressure and awake ambulatory blood pressure minus manual office blood pressure.

RESULTS

Cluster randomisation allocated 31 practices (252 patients) to manual office blood pressure and 36 practices (303 patients) to automated office blood pressure measurement. The most recent routine manual office blood pressure (149.5 (SD 10.8)/81.4 (8.3)) was higher than automated office blood pressure (135.6 (17.3)/77.7 (10.9)) (P < 0.001). In the control group, routine manual office blood pressure before enrollment (149.9 (10.7)/81.8 (8.5)) was reduced to 141.4 (14.6)/80.2 (9.5) after enrollment (P < 0.001/P = 0.01), but the reduction in the intervention group from manual office to automated office blood pressure was significantly greater (P < 0.001/P = 0.02). On the first study visit after enrollment, the estimated mean difference for the intervention group between the awake ambulatory systolic/diastolic blood pressure and automated office blood pressure (-2.3 (95% confidence interval -0.31 to -4.3)/-3.3 (-2.7 to -4.4)) was less (P = 0.006/P = 0.26) than the difference in the control group between the awake ambulatory blood pressure and the manual office blood pressure (-6.5 (-4.3 to -8.6)/-4.3 (-2.9 to -5.8)). Systolic/diastolic automated office blood pressure showed a stronger (P < 0.001) within group correlation (r = 0.34/r = 0.56) with awake ambulatory blood pressure after enrollment compared with manual office blood pressure versus awake ambulatory blood pressure before enrollment (r = 0.10/r = 0.40); the mean difference in r was 0.24 (0.12 to 0.36)/0.16 (0.07 to 0.25)). The between group correlation comparing diastolic automated office blood pressure and awake ambulatory blood pressure (r = 0.56) was stronger (P < 0.001) than that for manual office blood pressure versus awake ambulatory blood pressure (r = 0.30); the mean difference in r was 0.26 (0.09 to 0.41). Digit preference with readings ending in zero was substantially reduced by use of automated office blood pressure.

CONCLUSION

In compliant, otherwise healthy, primary care patients with systolic hypertension, introduction of automated office blood pressure into routine primary care significantly reduced the white coat response compared with the ongoing use of manual office blood pressure measurement. The quality and accuracy of automated office blood pressure in relation to the awake ambulatory blood pressure was also significantly better when compared with manual office blood pressure. Trial registration Clinical trials NCT 00214053.

Tyrosine hydroxylase polymorphism (C-824T) and hypertension: a population-based study

BACKGROUND

Sympathetic nervous system (SNS) overactivity is present in a large proportion of the hypertensive population and precedes the development of established hypertension. Variations in the proximal promoter of the tyrosine hydroxylase (TH) gene have been shown to influence biochemical and physiological traits in the SNS as well as hypertension.

METHODS

We investigated the relationship between a common single-nucleotide polymorphism (SNP) in the proximal TH promoter (C-824T) and blood pressure (BP) in a large general population sample, characterized by 24-h ambulatory BP (ABP) monitoring and office BP measurement.

RESULTS

The study population consisted of 1,221 women and 1,182 men, ages 41-71 years, without major cardiovascular diseases. Regarding the C-824T SNP, 32.4% had the C/C genotype, 50.0% the C/T genotype, and 17.6% the T/T genotype. The T/T genotype conferred an ~45% increase in relative risk of hypertension, defined by conventional criteria, compared with the C/C genotype, and participants with the T/T genotype had significantly higher mean (95% confidence interval (CI)) systolic BP (SBP) (138 (136-140) mm Hg vs. 135 (133-136)), diastolic BP (DBP) (88 (86-89) mm Hg vs. 85 (84-86)), and heart rate (68 (67-69) beats/min vs. 66 (65-67)) than participants with the C/C genotype (P < 0.05). BP, heart rate, and prevalence of hypertension were intermediate in participants with the C/T genotype. These effects were the same in women and men and whether BP was measured in the office or by 24-h ambulatory monitoring.

CONCLUSION

The C-824T SNP in the proximal TH promoter influences BP and prevalence of hypertension in the general population.

Clinical implications of ambulatory and home blood pressure monitoring

Because blood pressure (BP) is an ever changing hemodynamic phenomenon, a BP value, once measured at a physician's office (Office BP), is often unrepresentative of an individual's true BP status. Both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM) provide more accurate and reproducible estimate of BP, and produce stronger predictive ability for cardiovascular outcome than conventional office BP. Two BP measuring techniques, ABPM and HBPM have been widely in clinical use for the detection and management of hypertension. However, they have different advantages and limitations in practice. At present, it has become crucial to understand the characteristics and clinical implications of these BP measuring techniques for those responsible for the care of hypertensive patients.

Office and 24-h ambulatory blood pressure control by treatment in general practice: the 'Monitoraggio della pressione ARteriosa nella medicina TErritoriale' study

BACKGROUND

Guidelines recommend that blood pressure (BP) should be lowered in hypertensive patients to prevent cardiovascular accidents. Management of antihypertensive treatment by general practitioners is usually based on office measurements, which may not allow an assessment of BP control over 24 h, which requires ambulatory BP monitoring (ABPM) to be implemented. This is rarely done in general practice, and limited information is available on the consistency between the evaluations of the response to treatment provided by office measurement and by ABPM in this setting.

AIM

To assess concordance between office BP measurements and ABPM-based estimates of hypertension control in a general practice setting.

DESIGN OF STUDY

Prospective, comparative between techniques.

SETTING

General practice.

METHODS

Seventy-eight general practices, representative of all Italian regions, participated in this study by recruiting sequential hypertensive adults on stabilized treatment, who were subdivided into even groups with office BP, respectively, controlled or noncontrolled by treatment. In each individual, ABPM was applied by the general practitioner after appropriate training, and 24-h ABP values were defined as controlled or not according to current guidelines. Concordance between office and ABPM evaluation of BP control was assessed with kappa statistics. Positive and negative predictive values of office measurement versus ABPM were estimated.

RESULTS

Between July 2005 and November 2006, 190 general practitioners recruited 2059 hypertensive patients based on office BP measurements; in 1728 patients, a 24-h ABPM was performed, yielding 1524 recordings considered as valid for further analysis. The agreement between the assessment of BP control by office measurement and by ABPM was poor (kappa = 0.120), with office measurements showing a satisfactory positive predictive value (0.842) and a poor negative predictive value (0.278); the situation was worse in patients with three or more among the following features: male sex, age of at least 65 years, alcohol consumption, diabetes, and obesity (negative predictive value = 0.149).

CONCLUSION

In general practice, the agreement between assessment of BP control by treatment provided by office and ambulatory BP measurements is better in patients of 'uncontrolled' office BP than in 'controlled' office BP patients. This emphasizes the need for the larger use of out-of-office BP monitoring in a general practice setting, in particular, in patients considered as 'controlled' during consultation.